It is known in the electronics industry to use battery packs to store and subsequently supply energy to an electrical system. In traditional applications, batteries either customizes to particular applications, or multiple batteries are combined in a manner to provide the desired electrical characteristics. Typically, combining multiple batteries requires external connections, such as jumper tabs, soldered wiring, or welding. Commonly, battery assemblies are formed using automated processes that typically require a high level of control and repeatability, which also requires frequent calibration.
Battery systems may be used to provide power in a wide variety of applications. Examples of transportable applications include hybrid electric vehicles (HEV), plug-in HEVs, and electric vehicles (EV). Examples of stationary applications include backup power for telecommunications systems, uninterruptible power supplies (UPS), and distributed power generation applications.
Examples of the types of batteries that are used include nickel metal hydride (NiMH) batteries, lead-acid batteries, lithium batteries, lithium-ion batteries, and other types of batteries in a cylindrical form factor. A battery module includes a plurality of cells that are connected in series, parallel, or a combination thereof. The modules themselves may be connected in series, parallel, or a combination thereof in forming a complete battery pack.
Battery system integration poses multiple challenges in various disciplines. Most of the cost of a battery system lies with the battery cells. However assembly defects, such as, for example, misaligned welds, can result in expensive recalls wherein there is no opportunity to reuse the cells. Also, in low cost manufacturing markets, which can be large producers and consumers of battery packs, battery systems are prone to quality issues as their manufacturing techniques rely heavily on manual assembly processes. An error-proof, manual assembly design that can easily be automated is key for successful production.
When fasteners are used to connect bus bars to battery cells, a large size battery pack can end up with thousands of fasteners, all which must be torqued down to the correct torque value with the risk of vibrations loosening a metal fastener that can cause a short.
Modules are often externally connected by bus bars or cables, with cables being a cheaper option. However cables must be restrained to prevent loosening of the fasteners and chafing of the cables against other parts of the battery system. To restrain the cables at the lug terminal connecting it to the module, a two-hole lug terminal is commonly employed. To keep all modules the same, this requires all module-connecting bus bars to also have two holes, which doubles the amount of fasteners used in a battery pack and introduces added complexity to the bus bars used. The invention offers a built-in lug terminal restraint, saving the extra fastener.
Manufacturers of battery modules are always facing the dilemma of making small, highly-configurable modules versus large, well-integrated modules. The smaller modules offer more packaging options and can meet more diverse market demands. But the larger modules are more highly integrated, increasing the overall power to mass/volume and energy to mass/volume ratios by, in part, reducing the number of fasteners, mounting brackets and cables or complex bus bars. Aside from constrained packaging, the other issue with large format modules is the cost of replacement since the entire module is typically replaced.
The present invention is directed to overcome one or more of the problems as set forth above.